Two pairs of enantiomeric 3d-4f metal clusters, [Co(2)Ln[(R)/(S)-L](4)]center dot Cl-5 center dot(H2O)(2)center dot CH3OH center dot CH3CH2OH [Co(2)Ln; Ln = Gd (1S and 1R), Dy (2S and 2R)], were synthesized by the reaction of chiral Schiff-base ligand (R)/(S)-3-[(2-hydroxyb enzylidene) amino]propane-1,2-diol [(R)/(S)-HL] with CoCl2 center dot 6H(2)O and LnCl(3)center dot 6H(2)O. The circular dichroism spectra of (S)/(R)-Co-2 Ln display a mirror-symmetry effect with seven peaks at 210-800 nm, which can be ascribed to pi-pi* transitions, exciton coupling, charge-transfer transitions between ligands and Co3+, and characteristic d-d transitions of Co3+ ions. Interestingly, the chiral Co(2)Ln metal clusters display strong magnetic circular dichroism signals at room temperature. This work suggests that the chiromagnetic metal cluster is expected to show a strong magnetooptical response.